Organic load carrying additive

ABSTRACT

The lipid extract prepared by solvent extraction of microorganisms when added to lubricating oils improve the load carrying, anti-oxidant, and anti-corrosion properties of the oils.

United States Patent Forbes et a1.

[451 Apr. 25, 1972 ORGANIC LOAD CARRYING ADDITIVE Eric Simon Forbes, Knaphiil; Alan David Forbes, Woking, both of England The British Petroleum Company Limited, London, England Filed: Nov. 26, 1969 Appl, No.: 880,308

inventors:

Assignee:

Foreign Application Priority Data Dec. 6, 1968 Great Britain ..58,084/68 U.S. Cl ..252/49.9, 252/9, 252/325,

252/389, 252/400 int. Cl ..Cl0m l/46,Cl0m 1/32,C10m 3/40 Field of Search v.252/9, 32.5, 49.9, 389, 400

1,095,182 12/1967 Great Britain 252/9 Primary Examiner-Daniel E. Wyman Assistant Examiner-l. Vaughn Attorney-Morgan, Finnegan, Durham & Pine [57] ABSTRACT The lipid extract prepared by solvent extraction of micro-organisms when added to lubricating oils improve the load carrying, anti-oxidant, and anti-corrosion properties of the oils.

4 Claims, 1 Drawing Figure This invention relates to additives which can be added to lubricating oils to improve their properties, and to liquid lubricating compositions containing these additives. The additives of the present invention are produced from hydrocarbons by biochemical means.

It is known that it is possible to grow micro-organisms by the cultivation of micro-organisms on a hydrocarbon substrate in the presence of nutrient media and oxygen. The recovered micro-organisms may be purified by solvent extraction, and the purified micro-organisms are then available as food-stuff.

The waste products from the purification stage are a complex mixture of chemicals. Preferably the micro-organisms are yeasts.

We have now found that some of the waste products from the purification stage, referred to hereinafter as lipid extracts, when added to a lubricating base oil possess lubricating loadcarrying properties, antioxidant and anti-corrosion properties.

According to the invention there is provided a composition which comprises a blend of a lubricating base oil and a lipid extract as hereinafter defined.

By lipid extract is meant that portion of a micro-organism culture grown on a hydrocarbon substrate which is separated from the micro-organism by solvent extraction.

In order to separate the lipid extract from the micro-organisms, a solvent system consisting of a polar and non-polar solvent may be used. Preferably the polar solvent contains a hydroxyl group. Suitable solvent systems are ethanol/diethylether, methanol/chloroform, and isopropanol/n-hexane. Especially useful solvent systems are azeotropic mixtures of alcohols and hydrocarbons. Solvent systems consisting of alcohol/water mixtures are also useful, and the preferred solvent system is an azeotropic isopropanol/water system. The extraction may be carried out at room temperature.

Diethyl-ether may be used as a sole extractant but careful temperature control is required for efficient separation.

After the initial extraction of the lipid extract the solvents used can be evaporated off. When water is present in the solvent system an aqueous mixture is left which is then distilled to remove the water.

The hydrocarbons in which the yeast culture is grown are preferably petroleum fractions which can be obtained from crude oil. Preferably C or higher straight chain hydrocarbons are present in, or constitute, the hydrocarbon in which the micro-organisms are grown, and preferably the hydrocarbon contains from -15 percent of straight chain paraffins. Suitable methods for growing yeast cultures are described in UK.

Pats. Nos. 914,567, 914,568, 101,7584, l,0ll,7585, 1,021,697, 1,02 l ,698, 1,049,065, 1,049,066, l,049,067, 1,059,881, 1,059,886, 1,059,887, 1,059,891, 1,089,093,

The yeasts in this specification are classified according to the classification system outline in The Yeasts, a Taxonomic Study" by J. Lodder and W.J.W. Kreger-Van Rij, published by North Holland Publishing Co. (Amsterdam) I952).

Preferably when a yeast is employed this is of the family Cryptococcaceae and particularly of the sub-family Cryptococcoideae however, if desired there may be used, for example, ascosporogeneous yeasts of the sub-family Saccharomycoideae. Preferred genera of the Cryptoccoideae sub-family are Torulopsis (also known as Torula) and Candida. Preferred species of yeast are as follows. In particular it is preferred to use the specific stock of indicated Baarn reference number; these reference numbers refer to CBS stock held by the Central Bureau vor Schimmelculture, Baarn, Holland and to INRA stock held by the Institut National de la Recherche Agronomique, Paris, France.

Candida lipolytica CBS 610 Candida pulcherrima Candida utilis Candida utilis, Variati major CBS 841 Candida tropicalis CBS 2317 Torulopris colliculosa CBS 133 Hansenula anomala CBS "0 Ol'dium lactil Neurospora aitophila Mycoderma cancoillote lNRA: STV ll Of the above Candida lipolytica is particularly preferred.

if desired the micro-organism may be a mould. Suitable moulds are Penicillium and preferably there is used Penicillium expansum. Another suitable genus is Aspergillus.

If desired the micro-organism may be a bacterium.

Suitably the bacteria are of one of the orders:

Pseudomonadales, Eubacteriales and Actinomycetales.

Preferably the bacteria which are employed are of the families Corynebacteriaceae, Micrococcaceae, Achromobacteraceae, Actincymycetaoeae, Rhizobiaceae, Bacillaceae and Pseudomonadaceae. Preferred species are Bacillus megaterium, Bacillus subtilis and Pseudomonas aeruginosa. Other spe cies which may be employed include:

Bacillus amylobacter Pseudomonas natriegens Arthrobacter sp.

M icrococcus sp.

Corynebacterium sp.

Pseudomonas syringae Xanthemonas begeniae Flavobacterium devorans Acetobacter sp.

Actinomyces sp.

Nocardia opaca It will usually be possible to separate the micro-organism, contaminated with some unmetabolized feedstock and aqueous nutrient medium, from the bulk of the unmetabolized feedstock fraction. Preferably the separation is achieved by means ofa decantation: additionally of alternatively centrifuging may be used.

The preferred hydrocarbons in which the micro-organism is grown are the hydrocarbon gas oil fractions obtained from crude petroleum, and normal paraffins, e.g., those obtained from gas oil fractions e.g., by means of a molecular sieve separation process. The lipid extract obtained by the solvent extraction process is preferably subjected to further treatment to separate and concentrate the compositions possessing better load-carrying or anti-corrosion properties from the others. Suitable separation techniques include solvent fractionating, dialysis and chromatography.

The first separation stage is preferably to remove any residual amounts of the hydrocarbon substrate, residual yeast or other impurities by shaking the lipid extract with an organic solvent preferably paraffin or ketone e.g., n-heptane or acetone to produce a purified lipid extract.

The purified lipid extract can then be split into various further fractions to concentrate and separate the more useful fractions, and to obtain fractions which will be soluble in the base oil which is to be used.

When it is desired to use the lipid extract as a load-carrying additive preferably the fractions containing the phospholipids are separated.

A preferred way of carrying out a preparation of useful fractions is to carry out a further solvent extraction using a second solvent for example, petroleum ethers to obtain further extracts. By choice of this second solvent it is possible to separate the fraction which would be soluble in the base oil to which it is proposed to add the lipid extract.

in a preferred method the solution obtained using the second solvent is contacted again with the first solvent to reprecipitate the dissolved lipid extracts. [t has been found that this reprecipitated fraction is the most suitable for use in mineral base oils.

The crude lipid extracts can also be split into various fractions by dialysis across a semi-permeable membrane, preferably a rubber membrane. This method can be used as an alternative to or in conjunction with the solvent extraction method and serves to purify and separate the more useful fractions of the crude lipid extracts.

The lubricating base oil preferably has a viscosity of 5 to l2 centistrokes at 210 F.

The lipid extract is preferably present in the lubricating oil/lipid extract blend in an amount of 0.05 to percent by wt. and more preferably (H to 5 percent.

It is a feature of the present invention that it enables a lubricating composition to be formed from a lubricating base oil and an additive which possesses load-carrying anti-oxidant and anti-corrosion properties.

Metal surfaces, especially ferrous surfaces, are liable to cor rosion, and various additives have been added to oils coming into contact with such surface to inhibit this corrosion.

Corrosion inhibiting additives are especially useful for adding to oils which come into contact with water and which can be contaminated by water. This problem occurs particularly in lubricating oils for steam turbine bearings and gears. in these cases the contaminant is likely to be sea-water which can readily cause severe corrosion of unprotected surfaces.

It is very surprising that the lipid extracts produced by the growth of micro-organisms on a hydrocarbon substrate should be useful as lubricating oil additives The invention will now be described with reference to the following example.

EXAMPLE 1 A yeast of the family Candida Tropicalis was grown in a gas oil of boiling range 300 to 400 C. in the presence of a nutrient medium containing nitrogen and phosphorus. During the growth period air was blown through the liquid mixture. As described in UK. Pat. No. 914,568.

When the growth had reached the desired stage as mea sured by the cellular density of the yeast the mixture was centrifuged. A pasty phase containing yeast cells impregnated with hydrocarbons and aqueous medium was thus separated. This pasty phase was washed with water to removed the bulk of the gas oil, and the product obtained heated to 8090 C. in a rapid current of air and ground to a powder.

The powder was treated by solvent extraction using a mixture of isopropanol, n hexane and water. The solids not removed by the extracting liquids are the purified food-yeasts and the extracting liquids contain the yeast lipids extract. The extracting liquids can then be treated in two ways. If they are allowed to settle, two phases are formed, an upper phase containing isopropyl alcohol, n-hexane, any residual gas oil and some of the yeast lipids extract and a lower phase consisting of, mainly, isopropyl alcohol, water and the remainder of the yeast lipids extract. The solvents can be evaporated off from both these phases to yield yeast lipids fractions A.10 and 8.11 as shown in the diagramv Alternately the extracting liquids can be subjected to distillation and all the solvent removed, prior to settling, to give a total yeast lipids extract, TL.9.

EXAMPLE 2 Lipids extract TL.9 prepared as in Example 1 was treated to the series of operations shown in the accompanying diagram. A number of fractions were thus obtained for testing as antiwear additives.

The dialysis was carried out across a rubber membrane for 24 or 48 hours using n-hexane as a solvent.

The various fractions isolated were added to a liquid paraffin and the composition formed was tested in the Shell fourball tester and wear-scar diameter measured after 60 minutes. The results shown in the following Table 1 clearly demonstrate the anti-wear properties of the yeast lipid fractions, the tri-cresyl phosphate, a conventional anti-wear additive, is included as a comparison.

EXAMPLE 3 The total yeast lipid extract TL.9 prepared as in Example I was subjected to the following separation stages to isolate various fractions having enhanced anti-corrosion properties.

Crude lipids extract TL.9 was dissolved in n-heptane to yield TL.9.31 freed from residual yeast and mineral salts. As described in the accompanying diagram.

The various fractions of the lipid extract obtained as above were dissolved in several base oils and were tested using test procedures lP US A and IP 135 B. These tests indicate the ability of the oil compositions to prevent rusting of ferrous materials by oil compositions contaminated with water.

Test procedure I? 35 A uses distilled water and IP 35 B uses sea-water and is a more severe test.

The results are shown in the following Table 2, and the results to the amount of rusting seen in the test piece.

Samples TL 96 D and TL 918 D are prepared by the same steps. TL 96 8, TL 937 A, TL 954 A, and TL 958 A are prepared by the same steps and TL 96 C and TL 918 C are prepared by the same steps. The different batch numbers for the same fraction refer to different batches produced by the same process.

EXAMPLE 4 Lipid extract TL 931 prepared as in the diagram was tested as anti-oxidant in inhibiting the oxidation of a phenylene oxide. Compositions with and without TL 9.31 were shaken in a flask immersed in a silicone oil bath at 200 C. with air passing through the flask at constant mass flow. The decrease in oxygen content of the air from the test flask was measured. The induction period, maximum rate of oxidation and the total oxygen uptake were determined. The results are shown below.

Sample A Squalane (0.8 g.) plus polyphenylene oxide 3-) Sample B Squalane (0.8 g.) plus polyphenylene oxide (2.3 g.) plus TL 9.3l (0.0l47 g.) i.e. LS percent weight. Temperature 200" C., air flow rate 65 ml./min. duration 2 hours.

Induction Maximum Rate Total Oxygen Sample Period of Oxidation Uptake (mins) (mol 0, moi sec") (mol O,/mol

squalane) A 0 0.55 2.3 B [6 0.47 1.8

The results show the antioxidant properties of the lipid extract.

TABLE 1 Nitrogen content Phosphorus of content Additive fraction additive, of additive. \i'cnr scar Solubility used, 2% weight percent percent diam. in in liquid concentration weightweight mm. pnraflin 0.71 1. 10 0. 40 F 3. 2 5. 10 0.34 S 0. 2i 0. 1 9.66 S 1.68 2. i4 0. 33 S 2. 05 4. 7 0. 41 F Nil Nil 0. Nil 8. 42 Cl. 35 S 0.70 10. 6 (J. 33 S 0. 7O 1. 06 0. 34 S 0. 70 1. 06 0. 44 S H? mrtlzans that suspension of the additive in the liquid paraffin was 1 are S means that. the additive was soluble in liquid paraffin.

0.5 percent weight concentration.

0.06 percent weight concentration.

TL 9 l8 A 0.5% liquid paraffin TL 9l8 A 1.0% liquid paraffin Nil TL 9 l8 A 2.0% liquid paraffin Nil TL 954 A l.0% liquid parafi'in 4% TL 958 A 1.0% liquid paraffin Nil TL 93l 2.0% liquid paraffin Nil TL 954 A 2.0% HB l25 15% TL 937 A 1.0% B0 l60/95 Nil 4% TL 937 A BO M0195 Spots TL 953 A [0% BG 65/l00 Nil In the table the base oil HB I was a solvent refined base oil of viscosity of l25 Redwood No. 1 secs. at 140 F. the base oil 160/95 was lubricating base oil of viscosity 160 Redwood No. 1 secs. at 140 F. and a viscosity index of 95 and the base oil BG 65/100 was a lubricating base oil of viscosity 6 Redwood No. 1 secs. at [40 F. and a viscosity index of 100.

The lipid extracts used showed marked ability to reduce corrosion even in the sever IP 135 B test.

We claim:

l. A lubricating composition which comprises a lubricating base oil and from 0.05 through 10 percent by weight based on the total weight of the composition of a lipid extract containing nitrogen and phosphorus and obtained by the solvent ex traction of a micro-organism culture grown on a hydrocarbon substrate.

2. A lubricating composition as claimed in claim 1 in which the said liquid extract is contacted with an organic liquid selected from paraffins and ketones to precipitate a purified lipid extract which is incorporated in the said base oil.

3. A lubricating composition as claimed in claim 1 in which the lubricating base oil has a viscosity of 5 to 12 centistrokes at 2 l0 F.

4. A lubricating composition as claimed in claim 1 in which the said hydrocarbon substrate is selected from gas oil fractions obtained by the distillation of crude petroleum and normal parafiins, and in which the micro-organism is a yeast.

UNITED STATES PATENT ()FFIQE CRTIFICTE 0F PatentN 3,658,702 Dated April 25, 1972 lnventoz-(s) Eric Simon Forbes and Alan David Forbes It: is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 49, "101,7584" should read 1,017,584 w Column 3, line 2, "centistrokes" should read --centistokes;

Column A, Table I, under the heading "Phosphorus content..."

- and on the line beginning with "TL9(2)", "10.6"

should read 1.06 and Column 5, line 15, "viscosity 6" should read viscosity 65 Signed and sealed this 25th day of (T1113, 1972a (SEAL) Attest:

EDWARD M..FLEIJCI IER,JRa ROBERT GOTTSCHALK Attssting Officer Commissioner of Patents gg 15 sassshmm OFFICE CERTIFICATE OF CORRECTION Patent No, 3,658,702 Dated April 25, 1972 Inventor(s) Eric Simon Forbes and Alan David Forbes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 49, "101,7584" should read 1,017,584

Column 3, line 2, centistrokes" should read --centistokes--;

Column 4, Table I, under the heading "Phosphorus content..."

- and on the line beginning with "TL9(2)", "10.6"

should read 1.06 and Column 5, line 15, "viscosity 6" should read viscosity 65 Signed and sealed this 25th day of July 1972.

(SEAL) Attest:

EDWARD ILFLETCHERJR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,658,702 Dated April 25, 1972 Inventor(s) Eric Simon Forbes and Alan David Forbes It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r- Column 1, line 49, "101, 7584" should read 1,017,584 1 Column 3, line 2, "centistrokes" should read --centist0kes--; Column A, Table I, under the heading "Phosphorus content.

and on the line beginning with "TL9(2)", "10.6" should read 1.06 and Column 5, line 15, "viscosity 6" should read viscosity 65 Signed and sealed this 25th day of July 1972.

ISEAL) xttest:

:DWARD I I.FLETCHER,JR. ROBERT GOTTSCHALK ttesting Officer Commissioner of Patents 

2. A lubricating composition as claimed in claim 1 in which the said liquid extract is contacted with an organic liquid selected from paraffins and ketones to precipitate a purified lipid extract which is incorporated in the said base oil.
 3. A lubricating composition as claimed in claim 1 in which the lubricating base oil has a viscosity of 5 to 12 centistrokes at 210* F.
 4. A lubricating composition as claimed in claim 1 in which the said hydrocarbon substrate is selected from gas oil fractions obtained by the distillation of crude petroleum and normal paraffins, and in which the micro-organism is a yeast. 